package com.hxkcloud.patient.httpcache;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Log;
import android.widget.ImageView;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Collections;
import java.util.Map;
import java.util.WeakHashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * 主要流程是先从内存缓存中查找，若没有再开线程，从文件缓存中查找都没有则从指定的url中查找，
 * 并对bitmap进行处理，最后通过下面方法对UI进行更新操作。
 * 
 * @author Alex Huang
 * @email huangyu407@qq.com
 * @date 2014-9-24
 */
public class HttpImageLoader {
	private static final String TAG = HttpImageLoader.class.getName();

	MemoryCache memoryCache = new MemoryCache();
	FileCache fileCache;
	private Map<ImageView, String> imageViews = Collections
			.synchronizedMap(new WeakHashMap<ImageView, String>());

	// 线程池
	ExecutorService executorService;

	// 当进入listview时默认的图片，可换成你自己的默认图片
	int stub_id;

	public HttpImageLoader(Context context, int defaultPicRes) {
		this.stub_id = defaultPicRes;
		fileCache = new FileCache(context);
		executorService = Executors.newFixedThreadPool(5);
	}


	public void setDefaultImage(int defaultPicRes){
		this.stub_id = defaultPicRes;
	}
	// 最主要的方法
	public void displayImage(String url, ImageView imageView) {
		displayImage(url, imageView, null);
	}


	public void displayImage(String url, ImageView imageView,
                             HttpImageLoaderHandler handler) {
		imageViews.put(imageView, url);

		// 先从内存缓存中查找
		Bitmap bitmap = memoryCache.get(url);

		// 直接从文件缓存中查找是否有
		if (bitmap == null) {
			try {
				File f = fileCache.getFile(url);
				bitmap = decodeFile(f);
				if (bitmap != null)
					memoryCache.put(url, bitmap);
			} catch (Exception e) {
				Log.e(TAG, e.getMessage() + "");
			}
		}

		if (bitmap != null) {
			if (handler != null) {
				bitmap = handler.getBitmap(bitmap);
			}
			imageView.setImageBitmap(bitmap);
		} else {
			// 若没有的话则开启新线程加载图片
			queuePhoto(url, imageView, handler);
			imageView.setImageResource(stub_id);
		}
	}



	private void queuePhoto(String url, ImageView imageView,
                            HttpImageLoaderHandler handler) {
		PhotoToLoad p = new PhotoToLoad(url, imageView);
		executorService.submit(new PhotosLoader(p, handler));
	}



	public Bitmap getBitmap(String url) {
		File f = fileCache.getFile(url);

		// 先从文件缓存中查找是否有
		Bitmap b = decodeFile(f);
		if (b != null)
			return b;

		// 最后从指定的url中下载图片
		try {
			Bitmap bitmap = null;
			URL imageUrl = new URL(url);
			HttpURLConnection conn = (HttpURLConnection) imageUrl
					.openConnection();
			conn.setConnectTimeout(30000);
			conn.setReadTimeout(30000);
			conn.setInstanceFollowRedirects(true);
			InputStream is = conn.getInputStream();
			OutputStream os = new FileOutputStream(f);
			CopyStream(is, os);
			os.close();
			bitmap = decodeFile(f);
			return bitmap;
		} catch (Exception ex) {
			ex.printStackTrace();
			return null;
		}
	}

	/**
	 * 取得从网络下载的本地图片文件
	 * 
	 * @param url
	 * @return
	 */
	public File loadAndGetFile(String url) {
		getBitmap(url);
		return fileCache.getFile(url);
	}



	// decode这个图片并且按比例缩放以减少内存消耗，虚拟机对每张图片的缓存大小也是有限制的
	private Bitmap decodeFile(File f) {
		try {
			// decode image size
			BitmapFactory.Options o = new BitmapFactory.Options();
			o.inJustDecodeBounds = true;
			BitmapFactory.decodeStream(new FileInputStream(f), null, o);

			// Find the correct scale value. It should be the power of 2.
			final int REQUIRED_SIZE = 1280;
			int width_tmp = o.outWidth, height_tmp = o.outHeight;
			int scale = 1;
			while (true) {
				if (width_tmp / 2 < REQUIRED_SIZE
						|| height_tmp / 2 < REQUIRED_SIZE)
					break;
				width_tmp /= 2;
				height_tmp /= 2;
				scale *= 2;
			}

			// decode with inSampleSize
			o.inJustDecodeBounds = false;
			o.inSampleSize = scale;

			return BitmapFactory.decodeStream(new FileInputStream(f), null, o);
		} catch (FileNotFoundException e) {
		}
		return null;
	}

	// Task for the queue
	private class PhotoToLoad {
		public String url;
		public ImageView imageView;

		public PhotoToLoad(String u, ImageView i) {
			url = u;
			imageView = i;
		}
	}

	class PhotosLoader implements Runnable {
		PhotoToLoad photoToLoad;
		HttpImageLoaderHandler handler;

		PhotosLoader(PhotoToLoad photoToLoad, HttpImageLoaderHandler handler) {
			this.photoToLoad = photoToLoad;
			this.handler = handler;
		}

		@Override
		public void run() {
			if (imageViewReused(photoToLoad))
				return;
			Bitmap tempBmp = getBitmap(photoToLoad.url);
			Bitmap bmp = tempBmp;
			if (handler != null) {
				bmp = handler.getBitmap(tempBmp);
			}

			memoryCache.put(photoToLoad.url, tempBmp);
			if (imageViewReused(photoToLoad))
				return;
			BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad);
			// 更新的操作放在UI线程中
			Activity a = (Activity) photoToLoad.imageView.getContext();
			a.runOnUiThread(bd);
		}
	}



	/**
	 * 防止图片错位
	 * 
	 * @param photoToLoad
	 * @return
	 */
	boolean imageViewReused(PhotoToLoad photoToLoad) {
		String tag = imageViews.get(photoToLoad.imageView);
		if (tag == null || !tag.equals(photoToLoad.url))
			return true;
		return false;
	}

	// 用于在UI线程中更新界面
	class BitmapDisplayer implements Runnable {
		Bitmap bitmap;
		PhotoToLoad photoToLoad;

		public BitmapDisplayer(Bitmap b, PhotoToLoad p) {
			bitmap = b;
			photoToLoad = p;
		}

		@Override
		public void run() {
			if (imageViewReused(photoToLoad))
				return;
			if (bitmap != null)
				photoToLoad.imageView.setImageBitmap(bitmap);
			else
				photoToLoad.imageView.setImageResource(stub_id);
		}
	}

	public void clearCache() {
		memoryCache.clear();
		fileCache.clear();
	}

	public static void CopyStream(InputStream is, OutputStream os) {
		final int buffer_size = 1024;
		try {
			byte[] bytes = new byte[buffer_size];
			for (;;) {
				int count = is.read(bytes, 0, buffer_size);
				if (count == -1)
					break;
				os.write(bytes, 0, count);
			}
		} catch (Exception ex) {
			Log.e(TAG, ex.getMessage());
		}
	}
}
